The spraying module of the paving convoy known from JP 2002 322603A is a modified standard truck on which spraying module components are arranged on the bed of the chassis. A spraying bar faces the planum operating behind the rear end of the chassis. The truck has its own traction drive and travels between the road paver travelling behind the feeding assembly travelling ahead. The feeding assembly is supplied from the trucks delivering the paving material.
In the paving convoy known from AT-E-556344 B the spraying device is integrated into the feeding assembly which in turn is constituted by a shuttle buggy. The feeding assembly conveys paving material over the spraying bar of the spraying device to the road paver. The spraying bar sprays a bitumen emulsion within the working width of the paving screed on the planum but leaves the travelling lane of the undercarriage of the paver free. The paver has spraying bars behind the undercarriage for spraying bitumen emulsion in front of the lateral distribution device of the paver on the travelling lanes only. The shuttle buggy with integrated spraying device as well as the road paver with the integrated spraying bars both have individual special designs and are for these reasons structurally complicated and costly. In cases where no bitumen emulsion is needed, the feeder has to tow the unnecessary ballast of the spraying device, and as well spraying bars on the road paver are unnecessary ballast. The spraying device and the spraying bars on the road paver are contaminated during normal paving work and for this reason need complicated cleaning work after the termination of the work, irrespective of whether the work was carried out with or without spraying bitumen emulsion.
The road paver known from U.S. Pat. No. 5,279,500 A is equipped with a fully integrated spraying device including components needed for storage and deployment of the binding agent. The spraying bar comprises nozzles which co-operated with cyclically actuated closing elements for metering the sprayed bitumen emulsion. The spraying bar can be pivoted about an axis which extends laterally to the paving travelling direction and is designed to spray oval or rectangular spots on the planum.
DE 39 42 469 A discloses an assembly for metering and deploying a liquid binding agent, in particular, bitumen, on a road surface. The assembly is arranged on a mobile chassis and comprises components for storage and deployment purposes including a spraying bar. Metering is carried out by measuring the sprayed amount according to the principle of a mass through flow measurement and simultaneous measurement of the Coriolis force. This known assembly is used in an old-fashioned manner, namely to first spray the planum during a separate spraying cycle before a paving layer is cast later on after solidification of the binding material.
In recent times paving convoys have proven superior versatility which allows to continuously cast at least one paving layer with optimally high speed, since the casting process is not interfered with by the intermittent delivery and supply of the paving material. This concept is based on the fact that the road paver is supplied with the paving material with the help of a feeding assembly or shuttle buggy travelling ahead which in turn is supplied with a lot of paving material from intermittently shuttling trucks and, so to speak, constitutes a buffer store having a huge paving material storage volume. Although the technology of deploying a bitumen emulsion serving as the binder layer for the cast on paving layer has been improved such that the bitumen emulsion is spread first immediately before casting the paving layer (EP 049 260 B), which even is practised with the paving convoy of AT-E-556344 B, until now either a special shuttle buggy with an integrated spraying system and a special road paver with integrated spraying bars for the travelling lanes only have been widely used, or a standard shuttle buggy and a special road paver having an integrated complete spraying device (DE 41 01 417 B). Since, however, companies which have to cast paving layers with or without a binding layer have to live with the unnecessary ballast of the special machines or the significantly higher costs, in case of paving work without deploying a binding layer, but in some cases also have to carry out paving work with a binding layer, there is significant demand for a paving convoy concept comprising a standard shuttle buggy and a standard road paver but nevertheless offering the selective option to also produce a binding layer in a simple and fair cost way. This would be extremely desirable in order to improve the machine capacity utilisation and to expand the application spectrum without unnecessary ballast or unnecessary supplementary cleaning work, and, in particular, with a reduction of the basic cost for the machines.